Abundant moisture is one again headed for the Eastern Sierra as a storm from the Gulf of Alaska reaches back and phases with a Kona Low north of Hawaii. This pattern has been in the cards for well over a week now, and in some cases, there are still many unanswered questions,.

Where will the Bullseye be for the most precip over the Sierra?

How fast will the snow turn to rain and vice versa. The pattern is highlighted by the infamous Atmospheric River, foretold by the MJO over a week ago. For those that are interested in what the Atmospheric river is and does, SEE: https://www.esrl.noaa.gov/psd/arportal/about/

This Atmospheric River is especially important to Mammoth, as there is such a deep snowpack now. Any extra weighting on local roofs is especially concerning. The snow forecasted for Tuesday night will be highlighted by warm air advection precipitation. Warm moist air over-riding a cold air mass in place. The lift comes from the sierra and the dome of the pre-existing cold air. This generally is accompanied by steady light to possibly moderate precipitation here at 8000 feet. As the day goes on Wednesday, precipitation rates are likely to increase. If heavy snowfall continues in the high country Wednesday, it is possible that the snowfall may not turn to rain, in which case more snowfall could accumulate here in town then expected. I’ll have another update in the Morning….

The storm is capable to bring between 2 and 5 feet of new snowfall

Long Range:

The Weekend looks unsettled with snow showers and colder than normal temps..

Next week will be much colder than normal with an inside slider pattern developing. IE. Snow showers with highs in the 20s and lows in the single digits and teens….

We’re getting closer to the mid week period and the AR is definetly trending more toward the Central and Southern Sierra for the upcoming week. The AR gets energized by a cold short wave coming from the Gulf of AK which stretches southwest and picked up energy from a Kona Low…Currenly north of the Hawaiian Islands. This is the source of the subtropical fetch that will combine with a colder more dynamic system, as the moisture approaches the central west coast. What the GFS solution suggests is to leave enough of the Kona energy intact so that short wave #2 or #3 can pick up additional moisture later in the week for an additional AR that following weekend. I have not seen the new ECMWF..so I do not know if this is a reasonable outlook….. Needless to say, Givin the possibility of an additional AR….the QPF is quite high on this mornings GFS run through the end of this week. The mid week storm is close enough in time to say that the Moutain has another good 3 to 5 feet coming mid week. This is going to be a warmer storm and so the snow level my go to 7500 feet by Wednesday afternoon…..more later…

Dr Howard and the Dweebs..,.,,,😳

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Yes…Its true! Just as you thought it was safe to go out side again another couple of storms are on the way. Winter Storm Warnings are hoisted by the NWS beginning at 4:00PM Friday through 10:00PM Sunday. For the Town, the combination of the two storms with the 2nd one Saturday night and Sunday being the colder and strongest, some 8 to 16 inches is expected. For Mammoth Mt, between 2 and 3 feet.

These two weather systems will bullseye the Northern Sierra best with Kirkwood getting the better shot! Nevertheless we will not complain with another 2 to 3 feet headed our way atop Old Woolly! Expect high temps in town in the mid 20s with lows in the mid teens…..

Next week brings the possibility of the AR for parts of CA. As touted 5 days ago, it favors Southern CA, however, the details have to be worked out….. For the most part, the storm will become warmer, before it turns colder again…The Southern Stream becomes confluent with the northern stream, so this is a heavy snow pattern for the Sierra.

I will not update until Monday unless I can’t stand it! 🙂

Here is a portion of the post for the extended outlook from a forecaster at WSFO-RENO at 2:00PM THURSDAY

A large scale high pressure anomaly continues to strengthen in the northern Pacific Ocean with a corresponding large scale trough over the western U.S. during the second half of next week. This will keep the door open for more strong storms to drop out of the
Gulf of Alaska and into the Sierra. During the same time the sub-tropical jet is forecast to strengthen over Southern California. This setup could allow for warm pacific moisture to combine with cold Alaskan air as a deep trough digs into the west coast. As the
system is currently being advertised by computer simulations, this is one of the Sierra`s classic heavy snow patterns. With both the sub-tropical and polar jets forecast to meet in California the storms will be very dynamic. This can mean a few different things, including that predictability can be challenging, especially when it comes to snow levels. It can also mean rapid heavy accumulations of snow. The current forecast is for snow levels to jump up as the system makes landfall and then rapidly drop again as cold air moves into the region. But, like I said, this is one of the areas where a lot of change could be possible in the forecast. There is still a good deal of uncertainty this far out, especially for down here in the valleys. But for the Sierra, it seems likely they will again be measuring snow in feet.

It’s over….At least a repreave. Short wave ridging moving in and there may have been a chirp from a blue bird. The powder is so deep today that you have to be careful when skiing or boarding off trail because of the possibility of immersion suffocation. So take a deep breath when down weighting and be sure to ski and board with a buddy. Official storms total 89 to 132 inches. Sorry Kirkwood…. we beat you on this one….The bullseye was the northern part of the Southern Sierra.

Other comments…

Mammoth is digging out today. You can really see the benefits of owning a Honda snowblower when you have to blow the snow 10 to 20 feet up on some of those berms. You don’t have to blow the same snow twice!

Ok……Enough folklore…

Weather discussion;

I have been touting the MJO the past several days. The equatorial Tropical Forcing is strengthening and is strong into the western pacific. It moves into the central pacific late next week.So currently in phase 7, then 8 Then 1 on MJO phase space. This tool lets you see beyond the 2 forecast models, giving insight and supporting changes that the global models come up with that you may question. As mentioned over the past week, the MJO is moving east, it is strong and it means business. It strongly suggests an atmospheric river, and in this case because of the pattern that is seasoned; for Southern California. When? Between Thursday and Saturday AM after St Valentine’s Day. The IOP looks to be Friday into Saturday AM. This looks to be a power house. However…. I will remind all that today is Wednesday and there is lots of time to adjust…..

For Mammoth:

The AR looks to be mainly south of Central CA. We will look to be on the northern flank of the hose. The core of the hose will be over Northern Baja. Nevertheless, the storm has the potential to bring another massive amount of snowfall to our mountain that weekend.

in the meantime…..a moderate storm will bring additional snowfall to the hi-country this weekend. Between the two storms, another 1 to 2 feet is possible….